Certain foodstuffs, liquids, pharmaceuticals, and other substances are sensitive to atmospheric conditions such that exposure to the atmosphere affects shelf life or product quality. For example, once a bottle of wine is “un-corked” its shelf life before spoilage is limited. While corked and unopened, a bottle of wine may last for years, decades, or more. Once opened, however, the shelf life can be as short as a day and last up to a week or so and the wine takes on a different, unpleasant taste.
It is generally understood that oxygen degrades exposed wine, and that degradation occurs due to a chemical reaction with the wine and oxygen and/or the presence of oxygen which enables bacterial growth that then degrades the wine. In either scenario, the culprit to spoliation is oxygen.
For users who intend to open a bottle of wine and not consume the entire bottle, there are a handful of methods commercially available to extend the opened shelf life of the wine. These can be classified into two general categories: vacuum preservation and “air displacement.”
In vacuum preservation methods, a low grade vacuum is applied to the headspace above the wine, removing as much air as possible from the headspace created as wine was removed from the bottle. This technique has gained mainstream acceptance for extending the shelf life of an opened bottle of wine. The duration is arguable, but it is generally believed that this method chemically alters the wine. Wines that have been preserved via this methodology are often believed to become “flat” and “tasteless” compared to their native state.
Air Displacement is a second method of wine preservation that can be employed. There are a number of manners in which this method is being accomplished commercially:                1) Replace the air void with an inert “hard” material and reseal. Examples of this method include:                    a. Pumping an “air-bladder” into the headspace of the wine bottle. In this method the air is replaced with an inert plastic (or other material) bladder that presses up against the top of the wine in the bottle.            b. Filling a bottle with “marbles” or an equivalent. By putting hard spheres (or other shapes) into the bottle, the wine and hard object displace air from the bottle. By placing enough of these into the bottle the residual air space can be eliminated and the bottle “corked” in the absence of air.                        2) Displacing the “air” with an inert gas. This is done from small home systems to large commercial systems. Nitrogen and Argon gases have been utilized to displace air from the wine bottles in order to preserve the shelf life of the wine.        
While the air displacement methods have proven effective at extending the shelf life of opened bottles of wine as well as preserving their original tastes and aromaticity, there are various drawbacks ranging from cleaning, appearance and cost. There remains a need for a simpler, cost effective system for preservation of oxygen-sensitive substances, including, but not limited to, wine.